This invention relates to an anti-rust cover for a disc rotor in a disc brake used for a vehicle, more particularly, to one which is improved in its attachability, eliminating erroneous attaching thereof, onto the dust cover. The improvement involves disposing a combination of engaging members, as a means of attaching the anti-rust cover onto the dust cover, on the inner surface of the anti-rust cover in the vicinity of its outer periphery. The combination is composed of at least three pieces in number and arranged on the outer and inner side alternatively in order to have fitted therebetween the outer periphery of the dust cover. The curled periphery of the dust cover is to be snugly fitted, in an easy and accurate manner, between the innerly and outerly arranged engaging members. A stable and fixed attaching of the anti-rust cover onto the dust cover by means of the novel combination of engaging members is the gist of the improvement, i.e., the essence of this invention, which has eliminated the disadvantages of the prior art.
A disc rotor in a vehicle disc brake which is rotated with a wheel in a body is usually made of case iron, so it is very likely to produce rust. Especially when a vehicle with such a disc rotor is transported in an ocean going vessel, it is often subjected to sea wind containing much salt while it is in waiting for the loading at the pier. In the meantime the disc rotor is likely to be rusted.
The rust produced on the surface of the disc rotor causes the brake pad urging the same to be worn out and the friction coefficient to decrease, accompanying a byproblem of deterioration of the braking performance. As a measure of anti-rusting, an application of anti-rusting treatment on the surface of the disc rotor is generally considered. Coating of an anti-rusting material, for example, on its surface may result in a deficiency of the braking force through the decreasing of the friction coefficient of the rotor surface. It is therefore desirable that the disc rotor in the unloaded vehicle in the importing land still holds a remnant of anti-rusting material after the vehicle is delivered to the customer. If the anti-rusting material is removed earlier than the vehicle is delivered, the above-mentioned problem of rust producing conditions unsolved. For this reason, the coating of an anti-rusting material is usually regarded as impracticable. The general idea of preventing the rust, instead of the coating, has been to cover the disc rotor in order to physically protect it from rusting.
The general conventional practice has been therefore to attach an annular shaped anti-rust cover made of synthetic resin or cardboard to the dust cover, which is usually secured within a wheel on the inner side of the disc rotor (nearer to the center of the chassis), in order to cover the outer side of the disc rotor. This anti-rust cover, being attached on the outer periphery of the dust cover to cooperate therewith in enveloping the disc rotor for preventing the salty sea wind ingressing or flowing into the coverage, achieves a degree of anti-rusting effect.
The anti-rust cover is temporary, not being for permanent use, i.e., the anti-rusting while the vehicle is in the ocean going transportation route. So it must be attached before the transportation phase, during which the disc rotor and removed after the transportation subjected to rusting is over, that is, prior to the delivery to the customer. With the purpose mentioned above, conventional way of attaching the anti-rust cover onto the outer periphery of the dust cover was to dispose a plurality pairs of engaging members, on the inner surface of the anti-rust cover faced to the dust cover, each pair composed of an inner (inside) and outer (outside) engaging members arranged in confrontation to each other in the radial direction of the anti-rust cover. This way of arrangement of the engaging members in a mutually confronted position inherently results in a few troublesome problems. Fitting of the outer periphery of the dust cover accurately between the inner and outer engaging members is somewhat difficult operation; it is liable to rest on the inner side engaging member, instead of being snugly fitted therebetween. Such an inaccurate fixing of the anti-rust cover gives rise to an unexpected detaching thereof in the running of the vehicle; moreover the dust cover sometimes needs re-mounting. As the anti-rust cover is normally located in a very narrow space, within the wheel filled with some other deterrent parts, sandwiched between the disc rotor and the wheel disc, it is extremely difficult or troublesome to insert or reach out a hand into this narrow space or to handle it by lying on one's back beneath the vehicle chassis if. Even an accurate fitting were to be achieved, necessary requirement of a certain clearance between the outer and inner side engaging members, which is needed for the improvement of the attachability of the anti-rust cover, often impairs operator's feeling of snugness or right-fitting between the two. The above lack of right-fitting feeling may cause an erroneous attaching or sometimes a dropping of the anti-rust cover due to the vehicle vibration during the driving.